Enhanced optical output power by the silver localized surface plasmon coupling through side facets of micro-hole patterned InGaN/GaN light-emitting diodes.

Light extraction efficiency of GaN-based light emitting diodes were significantly enhanced using silver nanostructures incorporated in periodic micro-hole patterned multi quantum wells (MQWs). Our results show an enhancement of 60% in the wall-plug efficiency at an injection current of 100 mA when Ag nano-particles were deposited on side facet of MQWs passivated with SiO2. This improvement can be attributed to an increase in the spontaneous emission rate through resonance coupling between localized surface plasmons in Ag nano-particles and the excitons in MQWs.

Effect of strain relaxation in InGaN/GaN multi-quantum wells with self-assembled Pt nanoclusters.

We report effect of the strain relaxation in InGaN/GaN multi-quantum well (MQW) structures grown on platinum nanocluster-coated sapphire substrate (PNSS) by metal organic chemical vapor deposition. The photoluminescence (PL) intensity of InGaN/GaN MQWs on PNSS was significantly enhanced compared to that of the InGaN/GaN MQWs on flat sapphire substrate due to the reduction of defect density and residual strain by self-assembled Pt nanoclusters. We confirmed the reduction of strain-induced piezoelectric field by the power dependence of the PL in InGaN/GaN MQWs on PNSS. Cathodoluminescence shows that a large bright area with overall strong peak intensity is attributed to the suppression of In inhomogeneity and strain relaxation in InGaN/GaN MQWs on PNSS. Based on these results, we suggest that the self-assembled Pt nanocluster can be applied to increase the quantum efficiency through improved crystal quality and internal strain relaxation in MQWs.